Higher‐order Turbulence Statistics in the Earth's Magnetosheath and the Solar Wind using Magnetospheric Multiscale Observations

2018 ◽  
Author(s):  
R. Chhiber ◽  
A. Chasapis ◽  
R. Bandyopadhyay ◽  
T. N. Parashar ◽  
W. H. Matthaeus ◽  
...  
Keyword(s):  
Solar Wind ◽  
Higher Order ◽  
Turbulence Statistics ◽  
Magnetospheric Multiscale

scholarly journals Cold and Dense Plasma Sheet Caused by Solar Wind Entry: Direct Evidence

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 831
Author(s):  
Yue Yu ◽  
Zuzheng Chen ◽  
Fang Chen
Keyword(s):  
Solar Wind ◽  
Plasma Sheet ◽  
Cross Correlation ◽  
Direct Evidence ◽  
Dense Plasma ◽  
Ion Density ◽  
Average Value ◽  
Magnetospheric Multiscale ◽  
Cross Correlation Analysis ◽  
Solar Wind Entry

We present a coordinated observation with the Magnetospheric Multiscale (MMS) mission, located in the Earth’s magnetotail plasma sheet, and the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) mission, located in the solar wind, in order to understand the formation mechanism of the cold and dense plasma sheet (CDPS). MMS detected two CDPSs composed of two ion populations with different energies, where the energy of the cold ion population is the same as that of the solar wind measured by ARTEMIS. This feature directly indicates that the CDPSs are caused by the solar wind entry. In addition, He+ was observed in the CDPSs. The plasma density in these two CDPSs are ~1.8 cm−3 and ~10 cm−3, respectively, roughly 4–30 times the average value of a plasma sheet. We performed a cross-correlation analysis on the ion density of the CDPS and the solar wind, and we found that it takes 3.7–5.9 h for the solar wind to enter the plasma sheet. Such a coordinated observation confirms the previous speculation based on single-spacecraft measurements.

scholarly journals Relating the Solar Wind Turbulence Spectral Break at the Dissipation Range with an Upstream Spectral Bump at Planetary Bow Shocks

2022 ◽  
Vol 924 (2) ◽  
pp. 53
Author(s):  
M. Terres ◽  
Gang Li
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Space Environment ◽  
Mhd Turbulence ◽  
Solar Wind Turbulence ◽  
Spectral Break ◽  
Turbulent Spectrum ◽  
Magnetospheric Multiscale ◽  
Wind Turbulence ◽  
Bow Shocks

Abstract At scales much larger than the ion inertial scale and the gyroradius of thermal protons, the magnetohydrodynamic (MHD) theory is well equipped to describe the nature of solar wind turbulence. The turbulent spectrum itself is defined by a power law manifesting the energy cascading process. A break in the turbulence spectrum develops near-ion scales, signaling the onset of energy dissipation. The exact mechanism for the spectral break is still a matter of debate. In this work, we use the 20 Hz Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) magnetic field data during four planetary flybys at different heliocentric distances to examine the nature of the spectral break in the solar wind. We relate the spectral break frequencies of the solar wind MHD turbulence, found in the range of 0.3–0.7 Hz, with the well-known characteristic spectral bump at frequencies ∼1 Hz upstream of planetary bow shocks. Spectral breaks and spectral bumps during three planetary flybys are identified from the MESSENGER observations, with heliocentric distances in the range of 0.3–0.7 au. The MESSENGER observations are complemented by one Magnetospheric Multiscale observation made at 1 au. We find that the ratio of the spectral bump frequency to the spectral break frequency appears to be r- and B-independent. From this, we postulate that the wavenumber of the spectral break and the frequency of the spectral bump have the same dependence on the magnetic field strength ∣B∣. The implication of our work on the nature of the break scale is discussed.

Electrostatic waves in the shock ramp and their effect on plasma energetics.

2021 ◽  
Author(s):  
Ahmad Lalti ◽  
Yuri Khotyaintsev ◽  
Daniel Graham ◽  
Andris Vaivad ◽  
Andreas Johlander
Keyword(s):  
Solar Wind ◽  
Acoustic Waves ◽  
Cyclotron Frequency ◽  
Particle Interactions ◽  
Ion Acoustic Waves ◽  
Electrostatic Waves ◽  
Ion Plasma ◽  
Magnetospheric Multiscale ◽  
Bernstein Waves ◽  
Open Question

<p>Energy dissipation at collisionless shocks is still an open question. Wave particle interactions are believed to be at the heart of it, but the exact details are still to be figured out. One type of waves that is known to be an efficient dissipator of solar wind kinetic energy are electrostatic waves in the shock ramp, such as ion acoustic waves with frequency around the ion plasma frequency or Bernstein waves with frequency around the electron cyclotron frequency and its harmonics. The electric field of such waves is typically larger than 100 mV/m, large enough to disturb particle dynamics. In this study we use the magnetospheric multiscale (MMS) spacecraft, to investigate the source and evolution of electrostatic waves in the shock ramp of quasi-perpendicular super-critical shocks, and study their effect on solar wind thermalization.</p>

MMS observations of wave activity in the particle foreshock bubble foreshock region

2020 ◽  
Author(s):  
Mengmeng Wang ◽  
Quanqi Shi
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Speed ◽  
Wave Activity ◽  
Trailing Edge ◽  
Energetic Ions ◽  
Transient Phenomena ◽  
Magnetospheric Multiscale ◽  
Using Data ◽  
The Waves

<p>Foreshock bubbles (FBs) are kinetic transient phenomena formed due to the interaction between IMF discontinuities and backstreaming energetic ions in Earth’s foreshock region. FBs can be driven by both rotational discontinuities and tangential discontinuities and are typically observed under higher solar wind speed conditions. They play important roles in the solar wind-magnetosphere coupling because of very large dynamic pressure variations associated with them. The trailing edge of an FB is usually a fast shock which forms due to the expansion of the thermal plasma in the core. Using data from Magnetospheric Multiscale (MMS) mission, we investigate an FB structure with a particle foreshock region upstream its trailing edge. Distinct wave activity is observed in the particle foreshock region and wave analysis shows that the waves with periods of a few seconds may be generated by shock-reflected ion instabilities. The ions reflected at FB shock are observed and the acceleration mechanism needs to be analyzed.</p>

scholarly journals Wave vector analysis methods using multi-point measurements

2010 ◽  
Vol 17 (5) ◽  
pp. 383-394 ◽  
Author(s):  
Y. Narita ◽  
K.-H. Glassmeier ◽  
U. Motschmann
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wave Vector ◽  
Higher Order ◽  
Vector Analysis ◽  
Taylor’S Hypothesis ◽  
Recent Developments ◽  
The Mean ◽  
Point Data ◽  
Spacecraft Data

Abstract. Recent developments of multi-point measurements in space provide a means to analyze spacecraft data directly in the wave vector domain. For turbulence study this means that we are able to estimate energy, helicity, and higher order moments in the wave vector domain without assuming Taylor's hypothesis or axisymmetry around the mean magnetic field. The methods of the wave vector analysis are presented and applied to four-point data of Cluster in the solar wind.

scholarly journals Secondary Magnetic Reconnection at Earth’s Flank Magnetopause

2021 ◽  
Vol 8 ◽  
Author(s):  
B. B. Tang ◽  
W. Y. Li ◽  
C. Wang ◽  
Yu. V. Khotyaintsev ◽  
D. B. Graham ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Reconnection ◽  
Open Field ◽  
Global Scale ◽  
Diffusion Region ◽  
Magnetic Shear ◽  
Magnetospheric Multiscale ◽  
Field Lines ◽  
Secondary Ion ◽  
Magnetospheric Field

We report local secondary magnetic reconnection at Earth’s flank magnetopause by using the Magnetospheric Multiscale observations. This reconnection is found at the magnetopause boundary with a large magnetic shear between closed magnetospheric field lines and the open field lines generated by the primary magnetopause reconnection at large scales. Evidence of this secondary reconnection are presented, which include a secondary ion jet and the encounter of the electron diffusion region. Thus the observed secondary reconnection indicates a cross-scale process from a global scale to an electron scale. As the aurora brightening is also observed at the morning ionosphere, the present secondary reconnection suggests a new pathway for the entry of the solar wind into geospace, providing an important modification to the classic Dungey cycle.

Magnetic Curvature Analysis on Reconnection Related Structures at Earth’s Magnetopause

2020 ◽  
Author(s):  
Yi Qi ◽  
Christopher T. Russell ◽  
Robert J. Strangeway ◽  
Yingdong Jia ◽  
Roy B. Torbert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Solar Wind Plasma ◽  
Radius Of Curvature ◽  
Plasma Properties ◽  
Magnetospheric Multiscale ◽  
Reconnection Site ◽  
Field Lines ◽  
The Magnetic Field

<p>Magnetic reconnection is a mechanism that allows rapid and explosive energy transfer from the magnetic field to the plasma. The magnetopause is the interface between the shocked solar wind plasma and Earth’s magnetosphere. Reconnection enables the transport of momentum from the solar wind into Earth’s magnetosphere. Because of its importance in this regard, magnetic reconnection has been extensively studied in the past and is the primary goal of the ongoing Magnetospheric Multiscale (MMS) mission. During magnetic reconnection, the originally anti-parallel fields annihilate and reconnect in a thinned current sheet. In the vicinity of a reconnection site, a prominently increased curvature of the magnetic field (and smaller radius of curvature) marks the region where the particles start to deviate from their regular gyro-motion and become available for energy conversion. Before MMS, there were no closely separated multi-spacecraft missions capable of resolving these micro-scale curvature features, nor examining particle dynamics with sufficiently fast cadence.</p><p>In this study, we use measurements from the four MMS spacecraft to determine the curvature of the field lines and the plasma properties near the reconnection site. We use this method to study FTEs (flux ropes) on the magnetopause, and the interaction between co-existing FTEs. Our study not only improves our understanding of magnetic reconnection, but also resolves the relationship between FTEs and structures on the magnetopause.</p>

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